Blind robust watermark algorithm based on side-information of wavelet coefficients
一种基于小波系数边信息的鲁棒水印算法

In order to protect this copyright of the image, this paper presented a blind robust watermark algorithm based on the wavelet coefficients magnitude relationship. Transformed the host image into wavelet coefficients using the 3-level DWT, divided two blocks of the middle frequency band in DWT into a group of 8 wavelet coefficients in a pseudorandom manner using a key. Then embedded 1 bit watermark information in a group. Generated a secret key by magnitude relationship characteristic of two blocks and watermark. Saved the key and used to extract watermark. The experimental results show that the proposed algorithm is quite effective against JPEG compression, low-pass filtering, Gaussian noise and geometric attacks and the PSNR of watermark image is above 50 dB.